20NFR

20NFRX4-345A — Enclosure Design Reference & AI Summary
Generated by REDCATT Speaker Enclosure Tool
=== DRIVER IDENTITY ===
Code:         20NFRX4-345A
Platform:     20NFR
Description:  2-inch Full-Range | Neodymium | Glass Fiber Paper | 10W AES / 4Ω
Intended Use: TV sets, soundbars, column speaker arrays, small portable speakers,
              near-field consumer and commercial audio

=== THIELE-SMALL PARAMETERS ===
Fs:          185 Hz
Re:          3.6 Ω
Qes:         0.54
Qms:         10.3
Qts:         0.52
Vas:         0.09 L  (90 mL)
Sd:          11.34 cm²
Sensitivity: 83.03 dB (2.83V/1m) / 79.56 dB (1W/1m)
Mms:         1.37 g
Rms:         0.15 N·s/m
Cms:         0.54 mm/N
Bl:          3.24 T·m
Le:          0.08 mH
Xmax:        3.0 mm (one-way, peak)
Xmech:       5.5 mm
Xprot:       6.0 mm
Power:       10W AES / 20W continuous / 40W peak / 4Ω nominal
Voice Coil:  19mm on Kapton former
Cone:        Glass fiber reinforced paper
Surround:    Lightweight foam (large-excursion, low-mass design)
Spider:      Nomex
Basket:      Steel
Magnet:      Neodymium slug, U-cup steel circuit

=== DERIVED PARAMETERS ===
Volume displacement (Vd):         Sd × Xmax = 11.34 × 0.30 cm = 3.40 cm³
Inductance rolloff onset (f_Le):  Re / (2π × Le) = 3.6 / (2π × 0.00008) ≈ 7,162 Hz
Cone radius (r_cone):             √(Sd/π) = √(11.34/π) = 1.90 cm
Cone beaming onset (f_beam):      c / (π × r_cone) = 34,400 / (π × 1.90) ≈ 5,764 Hz
Max SPL @ 10W AES:                79.56 + 10·log₁₀(10) = 89.6 dB (1m)
Max SPL @ 20W continuous:         79.56 + 10·log₁₀(20) = 92.6 dB (1m)
Zobel network:                    R_z = 3.6 Ω (series), C_z = Le/Re² = 6.2 μF (series)

NOTE ON f_Le AND f_beam:
The inductance rolloff onset at 7,162 Hz and cone beaming at 5,764 Hz are both well
above the critical midrange band. This means the driver maintains a substantially flat
frequency response across the 200 Hz–5 kHz range with minimal correction required —
a significant advantage for a full-range driver without a tweeter.

=== ENCLOSURE RECOMMENDATION ===
Qts = 0.52 → Sealed micro-enclosures or free-air / open-back installations.

This is a full-range driver designed for embedded applications. Enclosure volumes are
in the millilitre range (not litres). Vented bass-reflex alignments are generally not
practical at this scale and are not recommended for the target application scenarios.

--- FREE-AIR / OPEN-BACK (TV panels, open-baffle column baffles) ---
In free air or an open-back baffle, the driver operates at its free-air Qts = 0.52
with a system -3dB roll-off at approximately 272 Hz. This is the standard installation
mode for flat-panel TV sets and many column speaker designs. DSP equalization applied
by the host device extends usable bass response; the manufacturer notes that with DSP,
the driver can be operated from approximately 60 Hz upward. The 3.0mm Xmax enables
the excursion needed to support bass boost at low frequencies within driver limits.

--- SEALED MICRO-ENCLOSURES ---
Three alignments are provided. All volumes are in millilitres (mL).
Port is not applicable — sealed only for this size class.

Alignment 1 — Portable / Hi-Fi (Butterworth, widest frequency extension)
  Cabinet volume (Vb):    106 mL
  System Qtc:             0.707
  System fc:              252 Hz
  System f-3dB:           252 Hz
  Notes: Requires the largest cavity of the three; best absolute bass extension;
         suited to compact portable speakers where cabinet volume is not severely constrained

Alignment 2 — Balanced (soundbar / near-field monitor)
  Cabinet volume (Vb):    33 mL
  System Qtc:             1.00
  System fc:              356 Hz
  System f-3dB:           280 Hz
  Notes: Very compact cavity; slightly rising response below fc provides natural
         bass presence before DSP correction; common in soundbar and multimedia designs

Alignment 3 — Compact (TV / embedded product / ultra-slim soundbar)
  Cabinet volume (Vb):    21 mL
  System Qtc:             1.20
  System fc:              427 Hz
  System f-3dB:           314 Hz
  Notes: Smallest practical sealed cavity for this driver; strong rising response
         requires DSP correction for flat playback; typical for TV set integration
         where physical depth is the primary design constraint

=== COLUMN SPEAKER / ARRAY GUIDANCE ===
In vertical line array (column speaker) applications, drivers share a common rear cavity
or are individually sealed. The 48mm overall driver diameter determines the minimum
center-to-center spacing in a column, which limits coherent array directivity:

  Maximum coherent array frequency: c / (2 × driver pitch)
                                    = 34,400 cm/s / (2 × 4.8 cm) ≈ 3,583 Hz ≈ 3.6 kHz

Above approximately 3.6 kHz, grating lobes will appear in the vertical radiation pattern.
The driver's cone beaming onset at 5,764 Hz provides natural high-frequency directivity
control above the grating lobe threshold. Rear cavity volume per driver in a column
enclosure is typically 20–40 mL, corresponding to Alignment 2 or 3 above.
The lightweight foam surround and low Mms (1.37 g) support good transient response
in the midrange band critical for speech intelligibility in column speaker applications.

=== CROSSOVER / DSP GUIDANCE ===
Full-range operation:  200 Hz – 17 kHz (per manufacturer; practical flat response
                       approximately 250 Hz – 12 kHz without DSP correction)
With DSP / host EQ:    From approximately 60 Hz with appropriate boost
High-pass filter:      Recommended at 80–120 Hz in sealed installations to prevent
                       over-excursion (Xmax = 3.0 mm; SPL at low frequencies with boost
                       requires careful excursion management at rated power)
Inductance rolloff:    Begins at ~7,162 Hz — negligible effect on response below 8 kHz
Cone beaming:          Onset at ~5,764 Hz; dispersion narrows above this frequency;
                       acceptable for near-field applications
Passive crossover:     Zobel network (3.6Ω + 6.2 μF in series across driver terminals)
                       compensates voice coil inductance for passive network designs

=== SUMMARY ===

The 20NFRX4-345A is a 2-inch full-range driver built around a neodymium slug magnetic circuit in a compact U-cup steel housing, designed for embedded consumer and commercial audio applications requiring a single-driver full-range solution. The glass fiber reinforced paper cone is driven by a 19mm voice coil on a Kapton former, with a lightweight foam surround engineered to deliver large-excursion capability with minimal moving mass (Mms = 1.37 g). Sensitivity is 79.56 dB (1W/1m) with a Bl product of 3.24 T·m, supporting 10W AES / 20W continuous power handling within a 48mm overall diameter and 29mm depth. Qts = 0.52 reflects a compliant suspension design suited to moderate-volume micro-enclosures, with a balanced motor-suspension ratio that supports controlled excursion across the operating band.